Safety envelope



Patented Feb. 26, 1929. 1

UNITED sures PATENT OFFICE.

Jenn HILMER ELFVERSON, or sT'ocKHoLM, SWEDEN, ASSIGNOR T0 AXEL 'vALnlvrAn HOLM, or- STOCKHOLM, SWEDEN.

SAFETY ENVELOPE.

Application filed August 27, 1927, Serial No. 215,966, and. in Sweden March 2d, 1926.

The present invention relates to a safety envelope the back of which cons1.sts,'in a manner previously known, of four flaps,

namely two side flaps, one lower flap and one upper flap. The invention has. for its purpose to provide an envelope which, when sealed, can not be opened and closed again,

without the envelope being damaged or deis sealed, each extra flap lies around the 31(1'.

jacent edge of the corresponding side flap and against both sides of the same, that is to say both against the outside and against the inside of the side flap. The said extra flaps are preferably made of such width that they lie around the edge of the corresponding side flap along the entire length or along the greater portion of the length of said edge.

An embodiment of the invention is illustrated in the accompanying drawing by way of example. Fig. 1 shows the piece of paper which is to be folded to form the envelope, the lines or edges along which the paper is to be folded being indicated by dotted-and dashed lines. Fig. 2 shows the back of the ready and sealed envelope, and Fig. 3 is a cross section of the envelope on the line III-III in Fig. 2.

Each envelope is made of a piece of paper, cloth or the like, of the shape shown in fulldrawn lines in Fig. 1. The center rectangular portion 12-34 of said piece is to form the front of the envelope, whereas the back of the envelope to be formed by the two side flaps 514; and 6-23, the upper flap 7-21 and the lower flap 8--43.

lVhen making the envelope the two side flaps,

514 and 6-23 are first folded inwards against each other along the dotted-anddashed lines 1l and 23, and their outer corners, which will overlap, as shown in Fig. 2, are fastened together in the ordinary manner by meansof gum or the like. The lower flap 8 18 is now folded up alongthe dotted-and-dashed line 43 and is fastened to the two side flaps in a manner further to be described here below, and finally the upper covered.

flap is folded down along the dotted-anddashed line 12.v I

According to the invention theupper flap is provided with two extra'fiaps 9 and 10, and the lower flap is provided with two corre sponding extra flaps 11 and 12, of the shape illustrated in Fig. 1. Said extra flaps, which in the instance illustrated have a substantially triangular shape, run out from the outer edges of the upper and lower flaps along the entire length or along the greater portion of the length of said edges. Each extra flap is folded at two places, namely along the dotted-and-dashed lines a and b in Fig. 1, and in opposite directions, namely along the line a inwards over the corresponding flap, and then outwards along the line 6. These outer portions of the flaps, that is to say the portions outside the lines Z), are then pushed under the side flaps previously joined to each other in the manner above described. In respect of the lower flap the said portions of the extra flaps are pushed under the side flaps during the making of the envelope, and in respect of the upper flap the said portions of the extra flaps are pushed under the side flaps when sealing the envelope, after the letter has been placed in the same. lVhen the envelope has been sealed, each extra flap will thus lie around the adjacent edge of the corresponding side flap and against both sides of the same, that is to say, against both the inside and the outside of the side flap, in the manner shown in Fig. 23in which 0 denotes the front of the envelope, (Z the side flap 514, 6 the upper flap 721, f the inner portion of the extra flap 9 between the folding lines a and b, and g the outer portion of the extra flap 9 outside the folding line b. The portions f and g are provided with gum on the sides directed towards the side flap tl,

that is to say. all extra flaps are provided with gum on their entire back sides as viewed in Fig. 1, and consequently, when the envelope is'being sealed, each extra flap will become fastened to the inside as well as to the outside of the adjacent side flap. As a result, it is impossible to open the envelope without damaging or deforming the same in such manner that it will instantly be dis- The folding lines Z) are chosen in such manner that when the envelope is sealed, said lines coincide or practically coincide with the corresponding edges of the side flaps, and the extra flaps have such width, reckoned along said folding lines, that they lie around the edge of the corresponding side flap along the entire length or the greater portion of the length of said edge. As shown in Fig. 2, when the envelope is sealed, the outer portions of corresponding extra flaps 9 and 11, and 10 and 12, will also partially overlap and become secured to each other over the triangular surfaces 13l4L-15 in Fig. 2, and will thus provide added security against the envelope being opened by an unauthorized person. For the same purpose the envelope may suitably be provided with a lining of thin paper.

I claim:

1. A safety envelope, comprising a rectangular front, and a back formed by two side flaps, one upper flap, and one lower flap, said upper flap and said lower flap being each provided with two extra flaps, each of said extra flaps being folded at two places and in opposite directions in such manner that when the envelope is sealed each extra flap lies around the adjacent edge of the corresponding side flap and against both sides of said side flap.

2. A safety envelope, comprising a rectangular front, and a back formed by two side flaps, one upper flap, and one lower flap said upper flap and said lower flap being each provided with two extra flaps, each of said extraflaps being folded at two places and in opposite directions in such manner that when the envelope is sealed each extra flap lies around the adjacent edge of the corresponding side flap and against both sides of said side flap, said extra flaps having such width that they lie around the edge of the corresponding side flap along substantially the entire length of said edge.

3. A safety envelope, comprising a rectangular front, and a back formed by two side flaps, one upper flap, and one lower flap, said upper flap and said lower flap being each provided with two extra flaps, each of said extra flaps being folded at two places and in opposite directions in such manner that when the envelope is sealed each extra flap lies around the adjacent edge of the corresponding side flap and against both sides of said side flap, said extra flaps having such size that when the envelope is sealed each extra flap on the upper flap overlaps the corre sponding extra flap on the lower flap inside the sealed envelope.

JOHN HILMER ELFVERSON. 

